The cozy will help you keep that second cup warm.
It slides right over the bottom and secures with a button through the handle of the Chemex. It will also fit just fine on the wood collar classic version.
Because it covers the whole bottom it also adds extra protection for the Chemex and whatever surface it is placed on.

This detailed knitting pattern is written in American knitting terms and includes photos of a finished piece.
There are instructions for 6 cup and 8 cup sizes.

Materials required,
• Approximately 50-60g of Aran weight yarn
• US 9 (5.5mm) needle – Can be worked by using magic loop method, 2 x circular needles or on double pointed needles
• Stitch markers
• Darning needle

Skill level is intermediate, you must be familiar with basic knitting stitches and techniques.
Stitches used,
• k – knit
• k2tog – knit 2 together
• kfb – knit into the front and back of the same stitch
• p – purl
• p2tog – purl 2 together
• pbf – purl into the back and front of the same stitch
• ssk – slip 1 knitwise, slip 1 purlwise, place back on left needle and knit together through the back loop st(s) – stitch(s)
• YO – yarn over